1. Field
One or more exemplary embodiments relate to a flexible display apparatus.
2. Description of the Related Art
In recent years, with the advent of an information-oriented society, display apparatuses configured to process a large amount of information and display the information have progressed quickly. Thus, various display apparatuses have been developed and highlighted.
A liquid crystal display (LCD) device, a plasma display panel (PDP) device, a field emission display (FED) device, and an electroluminescence display (ELD) device have been developed as display apparatuses. These display apparatuses are gradually being made to be relatively thin and lightweight and to consume low power. However, since the above-mentioned display apparatuses use a glass substrate to resist high heat generated during a fabrication process, there may be a technical limit to making the display apparatuses thin and lightweight or flexible.
Accordingly, much attention has recently been paid to development of a flexible display apparatus capable of retaining display performance even if the flexible display apparatus is bent like paper, by using a flexible material (e.g., a plastic film) which is capable of being folded and unfolded, instead of an inflexible glass substrate. The flexible display apparatus may be thin and lightweight, highly resistant to impact, and carried while being folded or rolled because the flexible display apparatus may be warped or bent. Further, the flexible display apparatus may be manufactured in any of various shapes and thus, widely applicable in the future.
The above-described flexible display apparatus may adopt a sensor configured to sense a shape deformation in order to measure an extent to which the flexible display apparatus is folded or bent and a direction in which the flexible display apparatus is folded or bent. As an example of a sensor configured to sense a deformation of a shape of the flexible display apparatus, a transparent electrode material applicable to touch screens or a hall sensor may be used.
A structure using the transparent electrode material may include a plurality of horizontal electrodes and a plurality of vertical electrodes that are arranged to intersect one another. The structure using the transparent electrode material may be utilized in a variety of ways, not only in display devices but also in the field of touch screens. In a shape deformation sensing technique using the transparent electrode material, since an additional ITO film is adhered to a top surface or bottom surface of a flexible display panel, a thickness of the flexible display apparatus may be bound to increase. When the thickness of the flexible display apparatus increases, a radius of curvature that may be allowed during a folding or bending operation may be limited. In particular, as the thickness of the flexible display apparatus increases, a displacement of an inner surface or outer surface may increase during the folding or bending operation, and the flexible display apparatus may be more likely be damaged. Further, since an indium tin oxide (ITO) film applied to a typical touch screen may detect a state of contact or non-contact with respect to a specific point, the ITO film may be technically limited when it comes to detecting simultaneous deformation (i.e., folding or bending operations) of several points or detecting a bending extent and direction.
In a structure using a hall sensor configured to sense a magnetic field, a plurality of hall sensors may be arranged in a widthwise or lengthwise direction of a flexible display apparatus, and a variation in the position of a magnetic body disposed at a specific point may be detected in order to sense a deformation of the flexible display apparatus. However, a shape deformation sensing structure using a hall sensor may be limited in that deformation may be sensed under specific conditions, for example, in that a deformation of the flexible display apparatus (e.g., carrying the flexible display apparatus while being rolled or folded) may be sensed only when the deformation occurs only in a direction in which hall sensors are arranged. Furthermore, it may be difficult for the structure using the hall sensor to sense a folding or bending extent and direction.